Now, the sun naturally emits light that ranges from the red to the blue ends of the light spectrum.

During the Spring and Summer, more of the blue spectrum of light makes it to earth because the sun is straight above in the sky.

Towards the end of Summer and in the Fall, as the sun tends to hang lower in the sky, more of the light that reaches earth falls within the red spectrum.

Most growers believe that change in the color spectrum of the light (to more red), and the increasing length of the night (dark periods) both help signal to the cannabis plant that it is time to start flowering and will affect your yields.

Basically, the plant is receiving signals that "winter is coming." Without these signals, a marijuana plant will stay in the vegetative stage for basically forever. In the wild, a marijuana plant always dies after one year (they don't survive through winter), but some indoor marijuana plants have been perpetually kept in the vegetative stage for years or even decades because they are never given the signals to start flowering..

As far as the color spectrum of light is concerned...

Blue light (for the vegetative stage) tends to make marijuana plants grow short and squat, with big healthy leaves.

This means that if possible, you will want to use grow lights that give off light in more of the blue spectrum during the beginning of your plant's life, and optimally you will then switch the lights to something that has more of the reds and oranges that cannabis likes during the flowering stage (or in fact almost any flowering plant).

Different strains are affected differently by the color spectrum of the light. Some are barely affected at all. Yet it's considered good form to choose lights in the proper light spectrum for the vegetative and flowering stages of the marijuana plant

By mimicking the sun's light as much as you can, you help ensure that your marijuana plants give you the biggest yields.

Yet when you must choose just one of the other, it's better to use the flowering light spectrum (more red) for the whole grow. However, many growers have proven that you can successfully grow buds in the blue light spectrum for the whole grow.

In other words, color spectrum is important, but it won't make or break your grow.

Note: I've used all types of grow lights during all stages of growing marijuana, and even when you're not using the "right" color spectrum, you will still produce potent buds with pretty much any strong grow light!

Weed is a relatively hardy plant in some ways, and so seemingly easy-to-kill in others. Don't worry, this artcile will show you what's important about grow lights so grow happy, healthy plants with huge yields.!

So if it's too much to worry about right now, than I encourage you to forget about color spectrum and focus on other factors for now (such as convenience and light intensity). Come back to color spectrum after you've got a handle on growing.